Google's knowledge of your location is much more detailed than only your phones GPS location.

- Billing addresses for Google Play

- Wifi and cellular networks seen by your Android devices

- IP addresses and other identifiers of all devices you used to access Google services (mobile and web)

- GPS metadata in pictures uploaded to Google Images and Drive

- Documents with addresses such as bills in your Google Drive and Gmail

And probably much more that I can't think of right now.

The Google Play store country however can be changed once per year, but you need a valid billing method originating from this country.